The present invention relates to a semiconductor device, a battery pack, and an electronic device, and particularly to a technique effectively applied to a semiconductor device for monitoring the state of a secondary battery.
It is necessary to inform a user of information indicating a battery state in the case of using a secondary battery as a power source for an electronic device such as a notebook computer. The information indicating the battery state includes information (Full Charge Capacity: FCC) indicating a capacity that can be extracted from the secondary battery in the case of discharging the secondary battery from a full charge state until a discharge cutoff voltage at a predetermined discharge rate, information (Remaining Capacity: RC) indicating the remaining capacity of the battery, and information (State of Charge: SOC) indicating the charge state of the battery. Accordingly, the electronic device incorporates the secondary battery and a state detection circuit for detecting the state of the secondary battery and outputting it to the outside, and the state information of the secondary battery detected by the state detection circuit is displayed on a display device such as an LCD (Liquid Crystal Display) and is used to determine whether or not to restrict the use of the secondary battery. For example, the following Patent Documents 1 and 2 disclose related arts for detecting the state of the battery.
Japanese Unexamined Patent Publication No. 2006-177764 (Patent Document 1) discloses a learning capacity correction method of a battery for, at the time of fully charging the battery from a predetermined charge start remaining capacity, detecting a charge capacity from the charge start remaining capacity to the full charge capacity, detecting an addition capacity obtained by adding the detected charge capacity to the charge start remaining capacity, comparing the detected addition capacity with the previous learning capacity, and using the addition capacity as the learning capacity if the difference between the addition capacity and the learning capacity exceeds a set error.
Japanese Unexamined Patent Publication No. Hei 5 (1993)-87896 (Patent Document 2) discloses a battery remaining-capacity detection/correction method in which there is provided a battery remaining-capacity correction unit for correcting a battery remaining-capacity calculation value obtained from a cumulative value of a consumption current from the battery based on an actual battery remaining capacity at a plurality of predetermined voltages of the battery, and there is displayed a value obtained by subtracting the cumulative value of the consumption current from the battery remaining-capacity calculation value corrected by the battery remaining-capacity correction unit based on the predetermined voltages.